Balance starter



Sept. 8, 1942. F. R. WASSBERG BALANCE STARTER Filed March 31, 1941 INVENTOR.

Patented Sept. 8, 1942 UNITED STATES PATENT OFFICE BALANCE STARTER Frank R. Wassberg, Coleraine, Minn.

Application March 31, 1941, Serial No. 386,193

Claims.

This invention relates to a starter designed primarily for use in connection with analytical balances.

It is the practice to mount balances of the type mentioned within glass cases where they are protected from dust and moisture. The starting of the balance has frequently been a problem, the usual practice being to open the case and fan with one of the hands against a pan of the balance or else to juggle the beam rest or to offset one of the pan arresters. None of these practiced methods, however, can be used continually without putting the balance out of adjustment because of wear or other causes.

An object of the present invention is to provide the balance with a starter which can be operated without opening the case, it being possible readily to install this starter in connection with a balance already in use.

With the foregoing and other objects in view claims, it being understood that changes may be made in the construction and arrangement of parts without departing from the spirit of the invention as claimed.

In the accompanying drawing the preferred form of the invention has been shown.

In said drawing Figure 1 is a view partly in section and partly in elevation showing a suspended pan of a balance engaged by a balance arm, the parts being in their normal positions.

Figure 2 is a plan view of the balance arm and the starter fingers associated therewith, a portion of the operating means being shown.

Figure 3 is a section showing the relative positions of the parts during the actuation of the pan by the starter fingers.

Figure 4 is an enlarged section on line 4-4, Figure 3.

Referring to the figures by characters of reference, I designates the base portion of the case in which the balance is mounted and one of the pans of the balance has been shown at 2. A bearing bracket 3 is mounted on the base at a convenient point and fulcrumed therein is a balance lever having a long arm 4 and a short arm 5. The free end of the long arm is positioned where it can touch the bottom of the pan 2 at the center thereof when said arm is in raised position. The short arm 5 of the balance arm has a depending shank 6 fixedly joined thereto and projecting through a slot 1 in the base I. The lower end of this shank is in the path of a push-rod 8 which is slidably mounted in guides 9 and has one end projecting through a wall of the case and provided with a button In. A guide sleeve II can be fixedly mounted on the case with the rod slidable therein and this sleeve has a slot [2 into which opens a notch l3. Rod 8 has a laterally extending pin l4 slidable in slot l2 but when the rod is in an intermediate position, it can be turned in one direction to move the pin l4 into the notch I3. A spring I5 is mounted on the rod between sleeve II and one of the guides 9 and serves to thrust against a collar 16 on the rod so as to hold the rod normally in one extreme position with the button or head l0 pressed outwardly away from the wall of the casing. At this time the pin I4 is in one end portion of the slot l2 as shown in Figure 1.

Mounted on the base I at one side of the bracket 3 is an elongated bracket I! having upstanding side fianges H! and I8 connected by a transverse pivot pin IS. A tiltable plate 20 is located between the flanges l8 and I8 and has side flanges 2| extending upwardly therefrom which are mounted to swing on the pin I9. This plate is normally inclined downwardly toward the base as shown particularly in Figure 1 and has light prongs 22 formed preferably of spring wire and extending from the plate along diverging lines. These prongs not only diverge laterally from each other but are also curved upwardly to points at one side of but adjacent to the free end of arm 4 so that they are thus located beneath the pan 2.

A lug 23 is extended laterally from the upper end of the tiltable plate 20 and projects under the arm 4 so as to be actuated thereby when the arm is lowered from its normal position.

It will be noted that the flange I8 does not extend throughout the length of the base ll but is cut away to provide a clearance in which the lug 23 can work.

When the parts are in their normal positions as shown in Figure 1 the pan 2 is contacted by the end of arm 4. By pushing button [0 inwardly until pin I4 arrives above notch l3 and then turning the rod 8 to position the pin in the notch, the shank 6 will be swung backwardly a sumcient distance to move the arm 4 downwardly against the lug 23. Thus the pan will be released for movement. If it does not move, however, the operator releases the pin l4 from notch I3 and pushes the rod 8 inwardly to its extreme position. This will cause the rod to push shank 6 backwardly a greater distance so that the free end of arm 4 will be moved downwardly and said arm will press on lug 23 and cause the plate 20 to tilt. Thus the prongs 22 will move upwardly and gently touch pan 2 so as to start the balance. This action is only momentary because as soon as the starting operation has been effected, rod 8 is released and the spring will return it to its intermediate position where, by turning the rod, it will be held until the operator is again ready to move the arm 4 back to its initial position against the pan.

Obviously by providing a starting device such as herein described, it becomes unnecessary to open the case in order to start the balance and, therefore, the balance bearings will not be injured nor the accuracy of the balance otherwise impaired.

What is claimed is:

l. The combination with the pan of a balance, of a balance starter including a lever positioned to engage the bottom of the pan, a resilient starting member tiltably supported below the pan, means for swinging the lever away from the pan, and means operated by the lever during the latter portion of said movement for thrusting said member against the pan.

2. The combination with the pan of a balance, of a tiltably mounted device, a resilient starting member extending therefrom under but normally spaced from the pan, a balance lever having an arm normally engaging the pan, means under the control of an operator for moving the lever away from the pan, and means operated by the lever during a portion of said movement for actuating the tiltable device and moving the starting member toward and against the pan.

3. The combination with the pan of a balance, of a tiltably mounted device, a resilient starting member extending therefrom under but normally spaced from the pan, a balance lever having an arm normally engaging the pan, means under the control of an operator for moving the lever away from the pan, and means operated by the lever during a portion of said movement for actuating the tiltable device and moving the starting member toward and against the pan, said first mentioned means including a push-rod, yielding means for holding the rod normally in one position, means for transmitting thrust from the rod to the lever, and means for holding the rod in an intermediate position with the lever and starting member in intermediate positions out of contact with the pan.

4. The combination with the pan of a balance, of a balance lever, a resilient starting device, a yieldingly restrained push button, and means operated by the movement of the button from and back to its normal position for moving the starting device and the lever alternately and separately into contact with the pan.

5. The combination with the pan of a balance, of a balance lever, a resilient starting device, a yieldingly restrained push button, means operated by the movement of the button from and back to its normal position for moving the starting device and the lever alternately and separately into contact with the pan, and means for holding both the lever and starting device in intermediate positions out of contact with the pan.

FRANK R. WASSBERG. 

